Operating temperatures and pressures for progressing cavity downhole pumps and motors have been generally considered to be limited by the adhesive used to bond the polymeric sleeve to the stator tube or housing. A seal gland of the type disclosed in U.S. Pat. No. 7,407,372 in a downhole pump or motor operates well in steam and high sand content wells where conventional bonding of the polymeric layer to the stator has failed.
Axial grooves in the inside wall of a cylindrical stator tube have been proposed to prevent rotation of the polymeric sleeve due to torque. These grooves are large relative to the stator tube, and were often a quarter or more of the tube width. Other manufacturers have sought to retain the polymeric sleeve on the tube by molding a flange on the end of the sleeve.
Relevant patents include U.S. Pat. Nos. 6,309,195, 7,131,827 and 7,407,372. Other patents of interest include U.S. Pat. Nos. 5,474,432, 4,313,717, 4,029,443, and 7,192,260. Asymmetric contouring of the polymeric liner is disclosed in U.S. Pat. No. 7,083,401.
The disadvantages of the prior art are overcome by the present invention, an improved progressing cavity pump/motor is hereinafter disclosed.